Self-collimation and subwavelength lensing in wavy two-dimensional photonic crystals

The equal-frequency surface of wavy two-dimensional (2D) photonic crystals (PC) is obtained by virtue of plane wave expansion method. From the equal-frequency surface, we find a iso-frequency contour of rectangular form. A flat dispersion relation exists at this frequency, which is suitable for the self-collimation. The finite- difference time-domain (FDTD) method is used to simulate the self-collimation in wavy 2DPC on which a Gaussian beam is incident at different angles. Subwavelength lensing by self-collimation is also available in wavy 2DPC. The resolution of 0.28 lambda is achieved when single source is employed in simulation. The resolution will gradually degrade as the source moves beyond the near-field domain.